Details

Autor(en) / Beteiligte

• Bauer, Amanda E.
• Hopkins, Andrew M.
• Gunawardhana, Madusha
• N. Taylor, Edward
• Baldry, Ivan
• Bamford, Steven P.
• Bland-Hawthorn, Joss
• Brough, Sarah
• Brown, Michael J. I.
• Cluver, Michelle E.
• Colless, Matthew
• Conselice, Christopher J.
• Croom, Scott
• Driver, Simon
• Foster, Caroline
• Jones, D. Heath
• Lara-Lopez, Maritza A.
• Liske, Jochen
• López-Sánchez, Ángel R.
• Loveday, Jon
• Norberg, Peder
• Owers, Matt S.
• Pimbblet, Kevin
• Robotham, Aaron
• Sansom, Anne E.
• Sharp, Rob

Titel

Galaxy And Mass Assembly (GAMA): linking star formation histories and stellar mass growth

Ist Teil von

• Monthly notices of the Royal Astronomical Society, 2013-09, Vol.434 (1), p.209-221

Ort / Verlag

London: Oxford University Press

Erscheinungsjahr

2013

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• We present evidence for stochastic star formation histories in low-mass (M * < 1010 M) galaxies from observations within the Galaxy And Mass Assembly (GAMA) survey. For ∼73 000 galaxies between 0.05 < z < 0.32, we calculate star formation rates (SFR) and specific star formation rates (SSFR = SFR/M *) from spectroscopic Hα measurements and apply dust corrections derived from Balmer decrements. We find a dependence of SSFR on stellar mass, such that SSFRs decrease with increasing stellar mass for star-forming galaxies, and for the full sample, SSFRs decrease as a stronger function of stellar mass. We use simple parametrizations of exponentially declining star formation histories to investigate the dependence on stellar mass of the star formation time-scale and the formation redshift. We find that parametrizations previously fit to samples of z ∼ 1 galaxies cannot recover the distributions of SSFRs and stellar masses observed in the GAMA sample between 0.05 < z < 0.32. In particular, a large number of low-mass (M * < 1010 M) galaxies are observed to have much higher SSFRs than can be explained by these simple models over the redshift range of 0.05 < z < 0.32, even when invoking mass-dependent staged evolution. For such a large number of galaxies to maintain low stellar masses, yet harbour such high SSFRs, requires the late onset of a weak underlying exponentially declining star formation history with stochastic bursts of star formation superimposed.